Praise be to Allah.
We put this question to Shaykh ‘Abd-Allaah ibn Jibreen (may Allaah preserve him) who answered as follows:
In our opinion this is not permissible except in cases of necessity, and on the condition that the men cannot see her. There should be a screen between her and them, and she should not soften her voice too much, because her voice may be ‘awrah. Women are not allowed to say Tasbeeh out loud in the prayer – if the imaam makes a mistake – instead they are commanded to clap [to draw the imaam’s attention to a mistake], lest their voices be recognized.
Shaykh ‘Abd-Allaah ibn Jibreen
At this point we would ask the brothers who are organizing these lectures: what need is there for a woman to give a lecture in front of a group of people which includes men? We hope that the answer will not be because they want to prove that Islam does not oppress women or to prove that they are open-minded and enlightened! Or any other weird and mistaken reasons that can never be used to justify opening the doors to fitnah (temptation) which Islam seeks to shut firmly. We constantly repeat our advice: organize your activities within the framework of sharee’ah. And Allaah is the Guide to the Straight Path. And Allaah knows best.